/Engine/Source/Runtime/Engine/Public/PrimitiveSceneProxy.h
Allows a scene proxy to override hit proxy ids and generate more than one hit proxy id per draw call Useful for sub-section selection (faces, vertices, bones, etc)
The vertex buffer to be use for custom hit proxy ids or null if not used. Each color represents an id in aHHitProxy
virtual const [FColorVertexBuffer](API\Runtime\Engine\Rendering\FColorVertexBuffer) * GetCustomHitProxyIdBuffer() const